The given diagram shows a blood capillary in close contact with structure Y. The relative concentration (in units) of carbon dioxide $\left({\mathrm{CO}}_2\right)$ and oxygen $\left({\mathrm{O}}_2\right)$ are given at three different sites.

Which of the following statements is correct?

Refer to the given diagram showing the cell cycle and answer the questions that follow.

(i) If the chromosome number at $X$ is $2n$, what will be the number of chromosomes at $Y?$
(ii) Which phase is the longest phase of the M phase?

Consider the following statements regarding gymnosperms.

(A) In gymnosperms, the male and female gametophytes have an independent existence.
(B) The multicellular female gametophyte is retained within the megasporangium.
(C) The gymnosperms are heterosporous.

Of these statements: